Day3：
只需兩行代碼解析html或xml信息??? 具體代碼實現:day3_1??? 注意BeautifulSoup的B和S需要大寫，因為python大小寫敏感
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import requests
r= requests.get("http://python123.io/ws/demo.html")
r.text
demo = r.text
from bs4 import BeautifulSoup
soup = BeautifulSoup(demo , "html.parser")
print(soup.prettify())
BeautifulSoup庫的基本元素：詳參html的基本信息
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from bs4 import BeautifulSoup??????? 語句含義：從bs4庫中引入一個BeautifulSoup的類型
下行遍歷，上行遍歷和平行遍歷：
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?爬取中國大學排名
import requests
from bs4 import BeautifulSoup
import bs4def getHTMLText(url):try:r = requests.get(url, timeout=30)r.raise_for_status()r.encoding = r.apparent_encodingreturn r.textexcept:return ""def fillUnivList(ulist, html):soup = BeautifulSoup(html, "html.parser")for tr in soup.find('tbody').children:if isinstance(tr, bs4.element.Tag):tds = tr('td')ulist.append([tds[0].string, tds[1].string, tds[3].string])def printUnivList(ulist, num):print("{:^10}\t{:^6}\t{:^10}".format("排名","學校名稱","總分"))for i in range(num):u=ulist[i]print("{:^10}\t{:^6}\t{:^10}".format(u[0],u[1],u[2]))def main():uinfo = []url = 'http://www.zuihaodaxue.cn/zuihaodaxuepaiming2016.html'html = getHTMLText(url)fillUnivList(uinfo, html)printUnivList(uinfo, 20) # 20 univs
main()
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